The present invention is directed generally to solar energy collectors and more particularly to a solar concentrating collector which will remain focused for a maximum portion of a day's sun hours without tracking movement.
Solar collectors can generally be classified as either concentrators or non-concentrators. A common form of non-concentrator is the flat plate collector wherein sunrays directly strike a flat absorber plate. But flat plate collector installations are restricted to locations having the required southern exposure.
Solar concentrators, including either a lens or arcuate reflective surface, are commercially available but many of these devices require a tracking mechanism for pivotally moving the device for following the sun's movement across the sky. The costs associated with the purchase and maintenance of such devices are believed to be prohibitive for general home use.
In recent years, various solar concentrators have been developed which do not require a tracking mechanism. These generally take the form of a concave reflective surface adapted to focus the sun's rays onto an absorber element. The reflective surfaces of such devices have taken the shape of a hyperbolic curve, a parabola combined with a semicircle and a parabola combined with a spiral, for example. Whereas these collectors do not require a tracking mechanism, certain problems are associated with their operation. The acceptance angle of some is so limited that the sun's rays can be received for only a relatively small portion of the daylight hours. In others, the concentration factor may be satisfactory only during a limited preferred time of day with the result that the average concentration factor is relatively small.
Accordingly, it is a primary object of the invention to provide an improved concentrating solar collector.
Another object is to provide a solar collector which is operative when installed to face a southerly, easterly or westerly direction.
A related object is to provide a solar collector adapted to operate without a tracking mechanism.
Another object is to provide a solar collector with a maximum average daily concentration factor.
Another object is to provide a solar collector having an acceptance angle so as to be operative during a maximum number of daytime hours.
A specific object is to provide a concentrating solar collector wherein the sun's rays are never reflected more than twice before striking the absorber thereof.
Finally, an object is to provide a concentrating solar collector which is economical to manufacture, simple in construction and efficient in operation.